Treat 'normal' blood pressure to save lives: study urges

PARIS – Millions of lives could be saved by givingblood pressure-lowering drugs to people at risk of heart attack and stroke,even if they have normal pressure, researchers said yesterday.

Based on an analysis of 123 medical trials involving more than 600,000people over two decades, the team called for an urgent review of existingtreatment guidelines.

"Our findings clearly show that treating blood pressure to a lower levelthan currently recommended could greatly reduce the incidence of cardiovasculardisease," said study lead author Kazem Rahimi of the University of Oxford.

This could "potentially save millions of lives."Blood pressure is recorded as two numbers, written as a ratio, for example140/90 mmHg (millimetres of mercury – the blood pressure unit).

The number on top is the "systolic" pressure inside the arteries when theheart beats, and the other the "diastolic" pressure between beats, when theheart is at rest and refilling with blood.

According to the American Heart Association, a "normal" pressure is lessthan 120/80, and becomes high from 140/90.

The study found that every 10 mmHg reduction in systolic blood pressurereduced the risk of heart attack by about a fifth, of stroke and heart failureby about a quarter, and the risk of death from any cause by 13 per cent.

"Importantly, these reductions in disease were similar across a wide rangeof high risk patients... irrespective of whether their blood pressure wasalready low (less than 130 mmHg) to begin with," they wrote.

People at high risk include those with a history of heart or arterydisease, stroke, diabetes or heart failure.

The researchers urged a revision of blood pressure guidelines, includingthose of the European Society of Hypertension which recently relaxed itsrecommended treatment level for high-risk patients from 130 to 140mmHg ofsystolic pressure.

It's relative

"Our results provide strong support for lowering blood pressure to systolicblood pressures less than 130 mmHg," wrote the team.

High blood pressure is the leading cause of heart disease and stroke, saidthe study authors, affecting more than a billion people worldwide and killingabout 9.4 million every year.

The benefits of lowering sustained high pressure are well established, butit has not been clear whether people with "normal" pressure levels would alsobenefit from treatment.

University of Sheffield cardiologist Tim Chico, who was not involved in thestudy, stressed that the benefits of treatment for a person with "normal" bloodpressure would depend on the individual's other risk factors for heart diseaseand stroke.

"For example, if you are already at a low risk, reducing this by 20 per cent isn't all that important, and probably isn't either cost-effective ordesirable," he said via the Science Media Centre.

"However, if you are at high risk (such as if you already havecardiovascular disease, diabetes or smoke) then a 20 per cent reduction in riskmakes a big difference and saves a lot of lives."

Anna Dominiczak, editor of the American Heart Association's journalHypertension, said she would call for a debate on blood pressure guidelinesbased on the study findings. — AFP